Automatc telephone system



J. WHIKSn AUTOMATIC TELEPHGNE SYSTEM. APPLICATION mm HEB. 4. 19:8.

Patented July 19, MIL

17 vanity? John ZfL/ZEkS UNITED sures PATENT OFFICE.

JOHN WICKS, OF GHIGIxGO, ILLINOIS, ASSIGN'O'R. TO A'UTdMAl'lPIC ELECTRIC COMPANY, OF CHICAGO, ILLINOIS, A. CORPOEA'IIUN U15 ILLINOIS.

AUTOMATG TELEPHONE lET'ltTEM.

Specification of Letters Ilia-tent.

Patented July 19, 1921.

useful Improvements in illutomutic Tole-- phone Systems, oi: which the following is specification.

M invention relates in eneral to 1mproved circuits for use in a system of the automatic type, but which is also adapted for use in manual or semiautomatic systems, especially systems of the latter type and is especially ed 7 cd for use in connection with a trunk line he'tween operators in two exchanges, where ccnnposii 1 thod of operation is employed. composite methods I mean that method of operation in which a trunk circuit has two separate and distinct circuits superimposed thereon, one over each of the two comiuctors of the trunk line.

Among the objects of my invention ore to provide an improved method of reaying" the ringing current between operators in two exchanges over a composite operating circuit, and to provide improved circuits for accomplishing this result.

In a system in which conil'iosite circuits are employed it is common practice to use either oneor the other or the superimposed circuits to operate an uulmrnatic switch a; the Far end of the toll trunk instead of employing the operators cord circuit at that end, and to use the other oi. the superior posed circuits to ope "ate other automatic switches or for telegraph messages as. the conditions may require. In such a s; it becomes necessary to provide some means for relaying the ringing current from one end to the other of the toll trunk over the talking circuit extended thereby and past the repeating coils which are included in said toll trunk. In my improved method, I accomplish this result by the use of merginal relays and a high voltage battery over one of the superimposed circuits as will he pointed out.

In the drawing. I have shown a toll trunk 0 between two toll boards A and This toll trunk extends from a jack before the toll operator A to a jack before the toll operator B. Superimposed on the toll trunk G are two separate circuits, one extending from the relay 2 in the upper left hand corner of the drawing through-one winding Oil; a composite coil associated with the toll trunh' I), over one conductor of said toll trunk through another composite coil at the far end of said toll trunk and. through the 69 relay in the p r right hand corner of the ri lfhe relays E2 and may he the line relays oi automatic selector or connector switches as desired, which switches may he used to extend connections from the conductors of the toll trunk C to any desired point. Another similar circuit is superimposed. upon said toll trunk over the other cohductor thereol old may he used to either operate automatic switches or for telegraph 70 purposes.

It will he understood that. only the essen tial circuits are shown in the drawing; and that the apparatus used is merely indicated in the customary diagrammatic nianneruli For a full. disclosure of the operation of autornutio switches ovencomposite circuits made to my U. S. Patent anted September 9, 1919.

List the operator A desires to establish a connection over the toll trunk C to some subscriber in the same exchange with the B operator, the opeutions which take place will he briefly described. The

.zl. operator in this case inserts the plug; of 35 h s: cor il i, which may he of any zip- 1 cred i into the jack lassociated with the toll trout; (J. Now in ccse the it. oper- :itor desires to have the B operator complete the commotion in the id exchange, the it. up rotor will press her usrml ringing hey "hrow generetor out over the plug and 1 l the toll trunk the generator current will i through the tip springs of the plug; on aclr. ,nn-ings ES and 6, condenser 7, impedunce coil 8, relay 9. springs 10 and 11, and ring; irings of the plug and jack to the other side of the generator. The condenser end impedance 8 forming low resistance path for generator current. the relay 9 will operate to close a circuit from ground through spri' and relay 13 to battery. Relay l3 upoi energizing over this circuit., opens the syn rs i l and 15 to prevent ringing current rorn. passing into the composite coils, and at the some time connects the high voltage battery Y in the SllpBTlIl'llJOSQd com posite circuit of the relay 16. Current now flows from said buttery Y through the springs 17 and '18 of relay 13, winding 19 of composite coils. conductor 20, wiiuling 21. of the composite coil in 13 exchange. springs 22 and, relay l6. relay 3. and key K in normal position to ground. This flow of current causes the marginal relay 16 to operate. to in turn close a circuit tor the ringing relay 24. The relay 2-11 upon energizing, connects direct generator through the trout contact of its springs and out through the normally closed contacts of the jack before the B operator to operate the drop 2.). The B operatorin response to this signal inserts her answering plug into the jack and completes the call in the usual manner.

In a system of this character it is often dosirable to permit the A operator to complete a connection with some subscriber in the l) exchai'ige independent of the B operator. in this case the A operator inserts the calling plug into the jack & in the usual manner and then instead of operating her ringing key to signal the B operator, she switches the key K from its normal position to close the composite operating circuit from the battery X through the calling device CD, lront contact of key K, relay 2 and 'over the previously traced circuit through relays 26. lb, and The A operator now operates the calling device CD to open and close the above traced circuit to operate an auton'iatic. switch at the B. exchange through the mediumo't the line relay 3. Although this circuit extends through the relays 2c and 16, these two relays will not operate at this time, as they are each of low resistance compared with relay 3, and are marginally adusted.

The relay 3 however operates in the usual manner to step a selector or connector switch with which it is associated to select, a. wanted line in the it exchange. The operation of this automatic switch extends the conductors 20 and 27 of the toll trunk t. to the called line over the conductors 28 and 25). it may be here noted that the transmission of impulses over the above traced composite circuit including the coils 19 and 21, has no el feet on the toll trunk l at its ends or upon the other composite circuit which is superimposed upon the conductor 27, as the composite coils, of which 19 and 91 are windings, are connected in the manner usual to such coils, and with the associated condensers and impedance bridges 31 and 32 entirely prevent interference between the circuits named.

Returning now to the established connection between the A. operator and a subscriber in the B exchange, as soon as said connec tion is completed, the A operator presses her ringing key to throw generator through the coil 9 as previously explained. The energization of the coil 9 has the same effect before mentioned, that is, the battery Y is connected in the operating circuit of the relay 3, which circuit also contains the relay 10. The battery Y being ol about double the voltage of the battery X. causes the relay us to operate to again close the circuit lf relay :H, which in turn connects ringing current to the drop 2.) and also to the conductors in and 25) which have been extended to a c: llcd subscriber. ".lhe called subscribens bell will now be operated in the usual manner and upon the response of said subscriber, conversation may he carried on between the A operator and said called subscriber. It will be understood that although as shown in the drawing the drop 25 is connected across the line at this time, the circuit of the drop 25 may be opened at the lirst selector when the switch is operated, so that when the operator at the A exchange rings on the line the drop will not be disturbed. This circuit may be opened or cut oil by any means well known in the art.

The bridges 31 and 32 are connected across the toll trunk in order to balance the same to assure a good conversational circuit. it will be seen that a call may also be extended from the ll operator to a subscriber in the A exchange or to the A operator direct in exactly the same manner by means of the calling device (.D' and battery X which control an automatic switch in the A exchange by means of line relay Also the ll operator may then relay ringing current to the A operator or to the called man in the it exchange by means of the relay 83, which is operated by ringing current and which controls the relay M to connect the battery Y in series with the relays 2 and 2G. lielayQtS responds to current from. batttery l to conne tgcncrator current to the called line or operator through the medium of the relay 35.

will be seen therefore that l have provided a. very simple and highly ellicient method of relaying ringing current from one exchange to another in a system in which composite coils and circuits are used for setting up automatic connections. Although I have shown my invention in connection with apparatus of a certain type it will be und-e stood that I do not wish to limit myself to the exact type shown, but that my improved method may be applied as well to any system of well known character without departing "from the spirit of my invention.

Having fully described and ascertained my invention. what ll consider to be new and desire to have protected by Letters Patent will be pointed out in the appended claims.

What l claim as my invention:

1. In a telephone system, a trunk line, automatic switches for extending connections from either end of said trunk line, op erating circuits for said switches having a. section in common in which is included one conductor of said trunk line, means for posed on one conductor of said trunk line,

relays in said circuit, deans for sending i1npulses from dillerent sources over said circuit to operate said relays, and means con trolled by one of said relays responsive to impulses from one of said sources for sig-- naling a called subscriber.

3. In a telephone system, a toll trunk comprising a pair of conductors, a composite circuit superimposed on one oi said conductors, automatic switches for attending a connection from one end of said toll trunk, means controlled over said composite circuit for operating said automatic switches, a relay in said composite circuit for connecting ringing current to one end of said toll trunk, and means for operating said relay by an impulse of increased current.

4. In a telephone system, a toll trunk COH3- prising a palrof conductors, a composite circuit superimposed on one of said conductors, automatic switches for extending a connection from one end of said toll trunk, means for sending impulses of current of one strength over said composite circuit to operate said automatic switches, and means for sending an impulse of increased strength over said composite circuit to signal a called subscriber.

5. In a telephone system, a toll trunk con1- prising a pair of conductors, a composite circuit superimposed on one of said conductors, automatic switches for extending a con nection from one end of said toll trunk, a relay in said ClI'Cllit for controlling the oporation of said switches, another relay in said circuit for connecting ringing current to the conductors of said toll trunk, said first relay responsive to impulses of one strength to operate said switches, and said second relay responsive to current of a greater strength to connect ringing current to said toll line.

6. In a telephone system, a two conductor trunk line, a composite circuit superimposed on one conductor of said trunk line, an automatic switch at each end of said trunk line for e tending connections from each end thereof, a relay in one end of said composite circuit for controlling the operation of one of said switches, another relay in said composite circuit for controlling the operation of the other of said switches, another relay at each end of: said composite circuit for connecting ringing current to each end of said trunk line, and means for operating said other relays by current of greater strength than that required to operate said first mentioned. relays.

7.. In a telephone system, a two conductor trunk line, a composite circuit superimposed on one conductor of said trunk line, an; automatic switch for extending a connection from one end of said trunk line, a relay in said composite circuit for controlling the operation of said switch, a second relay in said composite circuit for applying ringing current to one end of said trunk line, means ,for sending impulses of current over said composite circuit to operate said first relay to control said automatic switch, a third relay associated with said trunk line, responsive to alternating current, means for ap plying alternating current to one end of said trunk line to operate said third relay, and means controlled by said third relay for operating said second relay over said composite circuit to thereby signal a called subscriber.

8. In a telephone system,'a two conductor trunk line, a composite circuit superimposed on one conductor of said trunh line, an automatic switch for extending connection from one end of said. trunlr line, a relay in said composite circuit for controlling the operation of d switch, a second relay in said composite circuit for applying ringing current to one end of said trunk line, means for sending impulses of one strength over said composite circuit to operate said first relay to control. said automatic switch, a

third relay associated with said trunk line,

responsive to alternating current, means for applying alternating current to one end of said trunk line to operate said. third relay, and means controlled by said third relay for connecting current of increased strength to said composite circuit for operating said second relay to thereby signal a called subscriber.

9. In a telephone system, a trunk line, a signalat one end of said trunk line, a con t olling circuit for said signal superimposed on one conductor of said trunk line, a relay in said circuit, means controlled by alternating current for sending an impulse of direct current over said circuit to operate said. relay, and means controlled by said relay for operating said signal.

10. In a telephone system, a trunk line, automatic switches for extending connections from either end of said trunk line, an operating circuit for said switches superimposed'on one conductor of said trunk line, a relay in said circuit, means responsive to alternating current for sending an impulse of direct current over said circuit to operate said relay, and means controlled by said rela for signaling it called subscriber.

iuiitoinutie switches ioi "20 saidrehir,

3n the signaling current to connect he 35 the device responsive to the flowing in The conductor to L'OHllfiUv a cource 11. In u 'iJOiQPi'lODG system, a irunk line, .autoniutic switches for extenc' o; connections from either end of said trunk line, en operating circuit for said switches super- 5 imposed on one conductor of said trunk line,

a relay in said circuit means i. sponsive to alternatin g' current for sending an impulse of direct current over said circuit to operate said relay, mu? means eouirohed he said In Y for mmlvino" uherniuino current to 'she .eaiiec! line.

12. in u teiephone system, e trunk ii] i extending connections from either end oi suif' trunk line en I 0 ieratino circuit for said switches; suner-- in'iposed on one muhiciior of said trunk in A a relay in said circuit, means responsive to signaling current for scruiingg an impulse of direct current over suiii circuit (0 ogerete end means controlled by said rehr for applying 'gniiing current to the called .iine.

'13. A. teiephone exchziu 'c svstero con1prieing u relephone iine, :i' st tion thereoiu .an

illlPLdUlCfi device connected to the line,

Operalonceutroiimi means at the station for impressing alternating signaling: curreni upon "Hie line circuit :1 source of direcbcurrent, a, firs-i switching means res isive .1: source of direct curr in; to one conductor of the line circuit of one side of: the impedance device, and a second switching means associated with the line circuit on the other side of chrecb currenn of signaling current to the line cii'e'uiii.

14-. A tele'ihone exchen e 5 storm coin )115- ing u e iphone hue, n. plurality oi SiiI'LiOIlS thereon, an inipe hince device connected, thereto between two of: the seething a source of signaling current at each station, ope '11 tor-conerolled sxx'itcliingmenus at ouch o1" eheiwo stations for conneciiiu Hie source of signaling: current in the line circuit, 1L second shitiorls,

source of currci'it at one of the two :1 illiiii switching .ucunn i'ihcrmu' I SlNHHBU'U fo the connection null i; current to the hue at such shrtiou to cor nncci the second. source of current thin-cut [o one conductor of the portion of the iii between (he mo stations, zuniersitching nieuns xii the other of the two stations responsive in the curl-cut .f'hgwingr in such conducfjmr i: connect? ihe scuirce of signziiiug current thereon to the line circuit.

telephone ct'ichuiu "(l-111" I plural- 

